smaller wheels mean you can have more of them, and more smaller wheels simply have that many more places to touch the rails. The biggest and smallest wheels each only touch the rail in one single small spot. More wheels means more spots.Steam engines are definitely opposite. The smaller the driver size, the better tractive effort and traction the locomotive will produce. That's why switchers and low speed pullers have the smallest wheels.
The wheels on the foreign locomotive appeared much bigger than typical. I assume much larger than 44-inches. Maybe I am wrong.I haven't really done any diggin on theory but here is what I found when I surveyed wheel sizes.
I know there are some models I forgot but I needed road numbers to look them up and I was using numbers out of my head.
They shouldn't be or shouldn't have been. I did talk to a few old timers after I sent my last message to ask what the deal is with gear ratios and wheel sizes. Apparently EMD has many gear ratios. One of the common sizes is 62:15. An old timer who is long retired once told me that was about the same as 4.11's on a truck/car. The one fella has experience with industries' locomotives as well as rail roads. He said that some of the Mill's/Mine’s/Scrap Yards and the like use different ratios or smaller wheels than the ones I listed in a previous post. He said what they want to do is use 1 unit to pull say 20 cars. So they’re geared low or have small wheels. The locomotives will take off fast and appear to have a lot of power but because of that they will not go very fast. I guess it isn't uncommon for them to have a max speed of 30MPH. Even in this configuration the tractive effort is real good. As far as the "bigger" wheels there was a theory that they wore less and it would save money in the long run. I guess that's not necessarily true in the real world. They also said you will most likely only see 40-42" wheels so that the units are compatible with each other. Otherwise there will be instant wheel slip issues.The wheels on the foreign locomotive appeared much bigger than typical. I assume much larger then 44-inches.
Not a good description. Number of wheels is determined by axle load (how many wheels it takes to spread the locomotive's weight) and tractive effort/adhesion limits (a higher tractive effort locomotive needs more weight on drivers to not slip). The formula for steam tractive effort depends on cylinder dimensions, steam pressure and driver diameter. The number of axles doesn't figure into it. A larger wheel is like a long lever arm: it allows the end (the wheel rim) to turn faster but with less force.smaller wheels mean you can have more of them, and more smaller wheels simply have that many more places to touch the rails. The biggest and smallest wheels each only touch the rail in one single small spot. More wheels means more spots.
I may have seen it in my Facebook page and was not able to copy it and paste it. It may have been in Indonesia in Indonesian language. Maybe it was electric but I would have thoughthat I would have noticed electric or diesel.... Do you remember where the locomotive was from? Any other details about it? Specifically, was it a very old rather than new locomotive? Many old electrics had large wheels; there weren't many diesels made in that era, but I can think of one or two.
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